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Coastal communities at risk of tsunamis consider the merits of evacuating up

VANCOUVER—When the “big one” hits, coastal communities in B.C. could have just 20 minutes to reach high ground before a second disaster strikes: the earthquake could send a tsunami hurtling towards shore.

While many areas along the coast have natural evacuation zones within easy distance, in some communities — including a few on the west side of Vancouver Island — it may be difficult to clear the inundation zone in time.

A rendering of the Shoalwater Bay Tribe vertical tsunami evacuation tower set to be built in Tokeland, Wash. (Federal Emergency Management Age)

The tsunami was caused by an earthquake off the coast of Alaska and caused considerable damage. (Patrick Power/Courtesy of Alberni Valley Museum Photo PN09478)

The tsunami, caused by an earthquake off the coast of Alaska, shifted buildings off their foundations when it slammed into Port Alberni, B.C. in 1964. (Patrick Power/Courtesy of the Alberni Valley Museum, Photo PN09489)

When the ‘big one’ hits, coastal communities in B.C. could have just 20 minutes to reach high ground before a second disaster strikes: the earthquake could send a tsunami hurtling towards shore. (Jeremy Koreski)

About two-thirds of the Tofino area is in the tsunami inundation zone with limited access to natural high ground, said Keith Orchiston, the District of Tofino’s emergency program coordinator. The district is now looking at the feasibility of building a tsunami evacuation tower. (Michael Becker)

To help solve this potentially deadly conundrum in other parts of the world, emergency managers are looking at vertical evacuation options: towers built to withstand first an earthquake and then a wall of rushing water and debris.

Japan already has a number of these tsunami towers in place and the U.S. is investing in them too. The state of Washington broke ground on its first, above an elementary school gym in Westport in 2015. Last week the U.S. Federal Emergency Management Agency announced $2.2 million in funding for the Shoalwater Bay Tribe to build another in Tokeland, Wash., that could hold more than 380 people in the event of an emergency.

Now, Tofino, B.C. is looking at the feasibility of building a tower of its own.

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About two-thirds of the Tofino area is in the tsunami inundation zone with limited access to natural high ground, said Keith Orchiston, the District of Tofino’s emergency program coordinator.

So the “community would stand to benefit significantly from one of these structures,” he said.

East of Tofino, Port Alberni Mayor Mike Ruttan said a vertical evacuation tower would also benefit some areas his community.

“For some people it would be much safer, much faster for them to get to the top of an evacuation tower that it would be to physically get from where they are, up to the higher land,” he said.

Ruttan still remembers the devastation caused by the last tsunami to hit Port Alberni — and the smell it left behind.

It was 1964 and he was 13 years old. Three waves slammed the community, each one dragging up more of the seafloor and coating the community in an oily layer of muck. “You could smell it from quite a distance away,” he said.

After that, the community built a series of dykes, installed an early warning system, and today still practices evacuations. But there’s more they can do to prepare for the worst, and Ruttan said a tower is something to consider.

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But both he and Orchiston noted the high costs and suggested higher levels of government would need to chip in.

A spokesperson for Emergency Management BC said more research is needed but agreed vertical evacuation towers “may be effective in some communities on the west coast of Vancouver Island … where the tsunami hazard is high and where there will be less time for coastal communities to safely evacuate.”

The risk of a massive tsunami is “basically unquantifiable,” said Ryan Reynolds, a postdoctoral research fellow at the University of British Columbia, who studies community preparedness for natural hazards. They’re “more or less random events.”

There is a high risk that B.C. could experience a 9.0 magnitude earthquake along the Cascadia Subduction Zone at some point, which could trigger a tsunami. But a destructive wave could also be triggered by earthquakes further afield or even an underwater landslide, he said.

In fact, the 3.5-metre wave that hit Port Alberni in 1964 was triggered by an earthquake off the coast of Alaska. And, the city was placed under a tsunami alert earlier this year when another Alaskan earthquake struck, though the wave never came.

When another tsunami does strike Vancouver Island, evacuation towers “can be really useful in communities where either you won’t have a lot of time or where … it’s not very hilly,” Reynolds said.

Ioan Nistor, a coastal and hydraulic engineer based at the University of Ottawa who studies tsunami impact on infrastructure, identified eight communities on Vancouver Island that were highly vulnerable to tsunamis, including Tofino, a popular tourist destination.

While some tsunami towers are more simple structures with a set of stairs leading to a platform, Nistor said from his perspective they should be incorporated into other community infrastructure projects, such as schools or libraries, especially in smaller communities with fewer resources.

The key is “to make sure that your building or your structure can withstand the impact of a tsunami — and there are different types of impact,” he said.

In a place like Tofino, the building would also need to withstand the earthquake that could precede a tsunami, then the impact of multiple waves and heavy debris, such as cars and boats.

Prior to 1964, there was a massive earthquake and tsunami that struck the west coast in 1700 and Nistor said it will happen again eventually.

“The question is not if it will happen, it’s when it’s going to happen,” Nistor said.

But there’s a complacency in Canada because people haven’t experienced it in recent years, he said.

When an earthquake hit Chile in 2010, people knew to run for higher ground even though the alarm system was “botched.”

Canada’s public education efforts are lagging behind other countries, he said. “People need to be made aware of the danger of this phenomenon.”

Ainslie Cruickshank is a Vancouver-based reporter covering the environment. Follow her on Twitter: @ainscruickshank

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